1. Field of the Invention
The invention resides in the field of ground based transportation systems for passengers or freight and more particularly relates to apparatus for the programmable control of electric vehicles.
2. Description of the Prior Art
This invention relates to an improvement in the transportation system concept disclosed in U.S. Pat. No. 3,687,082 by the same applicant. The method and apparatus employed in that system provide for vehicle speed control by the sequential application of multiple electrical power sources of varying frequencies to an electric motor used to power the vehicle.
The vehicle sequentially receives power from a plurality of groups of guideway based busses connected to power supplies which generate a programmed succession of varying frequencies power waves.
The busses are reached through a vehicle connector extension or pickup, a brush or rotary device for example. As the vehicle moves forward on a guideway, separate insulated busses are sequentially connected to the propulsion motor which responds to the power supplied at each contact depending upon the power frequency encountered. The design parameters of motor, power supply frequency, buss spacing, and vehicle speed are selected to bring about a desired result of vehicle mobility pattern.
In particular, the power frequency supplied to each buss is sequentially varied such that, if the vehicle moves continuously at a desired speed, it is always supplied with power of a frequency that results in the motor producing sufficient torque to propel the vehicle at synchronous velocity. If the vehicle slows down or speeds up as a result of grade or load changes it will encounter a power frequency which will cause it to run faster or slower as the case may be. As the velocity of the vehicle adjusts, the motor will again synchronize with a power source frequency that will result in a desired rate of travel.